C++: Proper way to iterate over STL containers

Question

In my game engine project, I make extensive use of the STL, mostly of the std::string and std::vector classes.

In many cases, I have to ite

Answer 1

You might want to look at the standard algorithms.

For example

vector<mylass> myvec;

// some code where you add elements to your vector

for_each(myvec.begin(), myvec.end(), do_something_with_a_vector_element);

where do_something_with_a_vector_element is a function that does what goes in your loop

for example

void 
do_something_with_a_vector_element(const myclass& element)
{
 // I use my element here
}

The are lots of standard algorithms - see http://www.cplusplus.com/reference/algorithm/ - so most things are supported

Answer 2

• For random-access containers, it's not wrong.

• But you can use iterators instead.

  for (string::const_iterator it = theContainer.begin();
       it != theContainer.end(); ++it) {
      // do something with *it
  }
  

• There are some circumstances under which a compiler may optimize away the .size() (or .end() in the iterator case) calls (e.g. only const access, function is pure). But do not depend on it.